Timing Belt Pulley 25 HTD-5M/40-2 with taper-lock 1108

Timing Belt Pulley 25 HTD 5M/40-2 with taper-lock 1108

This timing belt pulley is relevant when an existing HTD belt drive needs to be updated, or when a new design requires a standardized pulley with a tapered bushing. This model has 40 teeth, HTD 5M profile with 5 mm tooth pitch, belt width 25 mm and fits tapered bushing 1108. The shaft range depends on the tapered bushing selected, and for this bushing type it ranges from Ø9 mm to Ø28 mm. It is particularly relevant in belt drives with smooth power transmission, where the belt teeth must engage the pulley uniformly and keep the movement synchronous.

The product is built according to the dimensions that apply to this specific size. The outer diameter of the gear pulley is Ø62.52 mm, the pitch diameter is Ø63.66 mm, and the total width b is 30.5 mm. The L dimension is 22.5 mm, and the R dimension is 8 mm. The outer diameter of the flange/plate is Ø71 mm. ND is not stated as a separate hub diameter for this variant. The inner diameter Di is Ø45 mm. The design is 16F, and the material is phosphated steel.

Technical specifications

• Profile: HTD 5M with 5 mm pitch
• Number of teeth: 40
• Belt width: 25 mm
• Version: 16F
• Taper bushing: 1108
• Shaft range with correct taper bushing: Ø9-28 mm
• Outer diameter of gear pulley: Ø62.52 mm
• Outer diameter flange/plate: Ø71 mm
• Material: Phosphated steel

Taper bushing selection

The tapered bushing is a practical solution when you want to avoid special drilling in timing belt pulley itself and instead choose a bushing according to the shaft diameter. For this timing belt pulley, tapered bushing 1108 must be used. This does not mean that the pulley is delivered with a fixed bore in the hub itself. In practice, the tapered bushing is selected with the bore that fits the shaft, and the bushing is then mounted in the conical seat of the pulley. For bushing 1108, the relevant shaft range is Ø9-28 mm. For example, if the shaft has a diameter within this range, the right bushing can be selected for the shaft, while timing belt pulley itself remains the same standard pulley.

It is important to distinguish between the pulley's taper bushing type and the final diameter of the shaft. The taper bushing 1108 tells you which physical bushing fits in the pulley, while the bore in the bushing tells you which shaft it fits on. When ordering, you should therefore check both: the taper-lock type of the timing belt pulley and the desired shaft diameter. If the taper bushing is chosen incorrectly, the pulley cannot be mounted correctly, even if the number of teeth and belt width match.

Profile, number of teeth and belt width

HTD 5M is a compact metric tooth profile, which is often used in small and medium-sized machines, where a precise belt drive with relatively small pulleys is desired. This pulley has 40 teeth, and this controls both the diameter and the ratio of the belt that will run in mesh with the pulley. The number of teeth is in the middle range for this series and provides a good balance between diameter, mesh and space consumption. The belt width is 25 mm, and the pulley must therefore be used in conjunction with a timing belt of the same width or a solution where the selected belt width is technically matched to the pulley grooves and flanges.

If you are replacing an older pulley, it is not enough to simply measure the outside diameter. The HTD profile, tooth pitch, number of teeth and belt width must match the belt. An HTD 5M pulley must be used with a belt of the same profile because the tooth shape is designed to engage the semi-circular teeth of the belt. An incorrect profile can cause noise, faster wear, poor engagement surface or, in the worst case, a belt drive that skips teeth under load.

Execution and dimensions in relation to the drawing

The pulley is made as 16F, which means it has a flange/plate to help the belt stay in place during operation. In technical drawings, it is especially b, L and R that cause confusion because they describe different width and hub dimensions. On this model, the b dimension is 30.5 mm, the L dimension is 22.5 mm and the R dimension is 8 mm. Use these dimensions together with the outer diameter Ø62.52 mm and the pitch diameter Ø63.66 mm when comparing the pulley to an existing drawing or an existing pulley.

The technical dimensions are therefore not just catalogue data, but practical selection parameters when the belt drive is to function in operation. If your current timing belt pulley has a flange, you should also check whether the new pulley is an F version. For this variant, the version is 16F. The flange diameter is Ø71 mm. Flanges can help with belt guidance, but they must not replace correct alignment of shafts and pulleys.

Material and surface

The material is phosphated steel. Phosphated steel provides a wear-resistant surface and is suitable for many normal machine tasks where the timing belt pulley must be able to withstand repeated operation. The phosphating gives a dark, technical surface, which also makes it easier to distinguish these tapered pulleys from standard aluminum pulleys. The choice of material has an impact on both strength, wear, weight and robustness of the construction. It is therefore important information when the pulley is to be used in an industrial belt drive and not just as a loose spare part.

With a larger number of teeth and larger profiles, the choice of material becomes extra important because the diameter, the torque of the belt drive and the load on the hub increase. This specific size must therefore be assessed together with the rest of the belt drive: motor power, speed, belt type, center distance, shaft diameter and operating environment. The pulley itself is a standardized component, but it only works optimally when it is selected together with the right belt and the right taper bushing.

Splice and practical check

Before splice, the axle, bushing and hub should be cleaned so that the contact surfaces are free of dirt, bars and old residues. Taper bushing 1108 is placed in the pulley's tapered bearing and the screws are tightened gradually and evenly so that the bushing retracts correctly. The selected bushing should have a bore that matches the axle, and the axle should normally have a suitable fit and groove if the design requires it. Overtightening or skewed splice can cause play, poor centering or unnecessary stress on the bearings.

Once the pulley is mounted, the belt tension should be checked according to the machine's requirements. A timing belt must not be too loose or too tight. Too low a tension can cause tooth skipping and imprecise operation, while too high a tension can cause unnecessary strain on bearings, shafts and the belt. Also check that the belt runs straight in the groove and that the pulleys are parallel. Even a correctly selected timing belt pulley can cause problems if the alignment is not correct.

Frequently Asked Technical Questions

Which taper bushing fits this pulley?

This pulley fits taper bushing 1108. This is the type of bushing to be used in the tapered hub of the pulley. Then choose a bushing with the bore that fits the axle. For this type, the axle range is from Ø9 mm to Ø28 mm.

What belt width should the pulley be used for?

The pulley is designed for a HTD 5M timing belt with a belt width of 25 mm. The belt width is important because the flanges, grooves and b-dimensions are made for this width. If a different width is used, it should only be done if the entire belt drive has been technically checked.

Is this a pulley with or without flange?

The design is 16F. The pulley is designed as 16F, which means it has a flange/plate to help the belt stay in place during operation. Always check this against the old pulley or the machine drawing, especially if the belt is in a vertical or side-loaded position.

Check before ordering

Always check five things before ordering: the HTD profile, the number of teeth, the belt width, the taper bushing number and the shaft diameter. For this model, the combination is HTD 5M, 40 teeth, 25 mm belt width and taper bushing 1108. The shaft range with the correct bushing is Ø9-28 mm. If this information matches your machine, you are much closer to a safe spare part without ordering the wrong part.

If you have an old pulley in hand, you can also compare the outer diameter Ø62.52 mm, pitch diameter Ø63.66 mm and b-dimension 30.5 mm. These measurements help to ensure that the pulley not only fits the belt and shaft, but also the physical space in the machine. If in doubt, it is an advantage to send pictures or measurements so that the profile, belt width and taper bushing can be assessed before the order is placed.